A data center is a collection of secure, fault-resistant resources that are accessed by users over a communications network (e.g., a wide area network (WAN) such as the Internet). By way of example only, the resources of a data center may comprise servers, storage, switches, routers, or modems. Often, data centers provide support for corporate websites and services, web hosting companies, telephony service providers, internet service providers, or application service providers.
Some data centers, such as Hewlett-Packard Company's Utility Data Center (UDC), provide for virtualization of the various resources included within a data center.
An issue that needs to be addressed within a data center is how to backup the data center, especially when the data center maintains data for multiple secure networks having different levels of security or belong to different trust domains.
One way to backup data within a data center is to perform a raw volume backup of an entire disk. While this provides a satisfactory means for restoring an entire disk, disaster recovery efforts are often of finer granularity (i.e., typically only a particular file or files needs to be recovered, or only a particular application needs to be recovered). Thus, raw volume backups often result in backing up more data than is needed, which is a waste of both data center resources and backup disks. In addition, restoring data from a raw volume backup is unnecessarily time-consuming when a user only needs to restore a subset of files.
Another way to backup data within a data center is to create a dedicated backup infrastructure for backing up disks. However, a problem with this sort of backup is that the backup infrastructure typically creates a shared network for backing up the disks, which is undesirable given that a data center disk may be shared by different secure networks that 1) are associated with different levels of security, or 2) belong to different trust domains. Creating a dedicated backup infrastructure also doubles the cost and complexity of a data center.